Fresh clashes have broken out in Syria despite the passing of a UN-backed deadline for a complete withdrawal of government troops and weapons.

Activists reported shelling in Homs and areas of northern Aleppo province, and unrest in the capital, Damascus.

Rights groups said 11 people had been killed on Tuesday.

Syria's Foreign Minister Walid Muallem, in Russia for talks, said Damascus had taken steps to adhere to the plan by withdrawing some troops.

He blamed "armed gangs" for the continuing violence.

Under the peace plan - negotiated by the UN and Arab League's special envoy on the Syrian crisis, Kofi Annan - Syrian troops were to have completed their withdrawal from population centres and stopped the use of heavy weaponry by Tuesday, ahead of a full ceasefire coming into place on Thursday.

Damascus had agreed to the deadline, but on Sunday demanded written guarantees first that its opponents would give up arms, along with a promise from foreign states not to fund them.

Analysis

By Jim MuirBBC News, Beirut

Mr Muallem's suggestion that a ceasefire should coincide with the arrival of international peace monitors is getting things completely out of the sequence envisaged by Kofi Annan.

That called for the government to take the first step in pulling back its forces, and the opposition would follow suit in applying a ceasefire by Thursday morning. The observers would then come in to monitor an existing peace, not be part of the stabilisation process in terms of going into a combat situation and trying to calm it themselves.

It indicates to me there is no clear way forward coming out of the meetings, unless there are things that have been decided behind the scenes. Everybody recognises the Annan peace plan went as far as anybody could go in providing a balanced, peaceful political solution. If this doesn't work its very hard to see how any other plan could.

Speaking after talks with his Russian counterpart, Mr Muallem said army units had been withdrawn from some areas, a number of detainees released and agreement reached on getting humanitarian aid to those in need.

But he said that "despite all these positive measures we noticed on a daily basis the escalation of opposition by the armed terrorist gangs".

He said a ceasefire could only come into force once a team of international observers had arrived, but also accused Turkey of supplying militant groups with weapons and allowing them to cross its borders, AFP reports.

Russian Foreign Minister Sergei Lavrov said the Syrian government "could have been more active and decisive" in implementing the plan, but that Mr Muallem had assured him Damascus was committed to it.

Success rested on those countries with influence over the opposition groups putting pressure on them to abide by a ceasefire as well, he said.

Ceasefire timetable

10 April: Government must withdraw troops and heavy weapons such as tanks from towns, cities and villages

Following 48 hours: Ceasefire to be implemented on the ground with the onus on the opposition to follow the government's lead

06:00 local time on 12 April: All forms of violence must be stopped on all sides

Next step: All parties to hold talks on a political solution

Russia is one of Syria's closest allies and as a permanent member of the UN Security Council has vetoed resolutions condemning Damascus.

France's foreign ministry described Mr Muallem's comments as "a fresh expression of this blatant and unacceptable lie" that Damascus was committed to the Annan plan and urged the international community to react against the "feeling of impunity".

'Assad thugs'

The UK-based Syrian Observatory for Human Rights said six civilians were killed by fresh shelling in Homs on Tuesday and another was shot dead in the city. It said another four people were killed in Kfar Zeita in central Hama province, while military activity was also reported in Aleppo province.

It may be too early to draw a definitive line under Kofi Annan's peace plan for Syria, but it is not looking in terribly good health

By Jonathan MarcusBBC Diplomatic Correspondent

One Damascus resident told the BBC that violence in the capital had doubled and that one protest was attacked by "Assad thugs".

"They opened fire and I think some people were injured. I expect more street fighting in the coming days," he said.

Mr Annan was visiting some of the Turkish camps on Tuesday.

The visit comes a day after several people in one camp were injured by shots fired across the border from inside Syria. Two people were also shot dead as they approached the border from the Syrian side.

Turkish Prime Minister Recep Tayyip Erdogan, on a trip to China, said the incidents were a "clear violation" of its borders and that his country would "take the necessary measures" in response.

Annan's six-point peace plan

1. Syrian-led political process to address the aspirations and concerns of the Syrian people

2. UN-supervised cessation of armed violence in all its forms by all parties to protect civilians

3. All parties to ensure provision of humanitarian assistance to all areas affected by the fighting, and implement a daily two-hour humanitarian pause

4. Authorities to intensify the pace and scale of release of arbitrarily detained persons

5. Authorities to ensure freedom of movement throughout the country for journalists

6. Authorities to respect freedom of association and the right to demonstrate peacefully

Turkey now hosts some 24,000 Syrians, including hundreds of army defectors, and has seen a sharp rise in the number of refugees coming over the border in the past week.

Separately, Lebanon has condemned the killing of a Lebanese cameraman, Ali Shaaban, who was shot on Lebanon's northern border with Syria.

The UN says more than 9,000 people have been killed in the uprising against Mr Assad's rule which began more than a year ago.

In February, the Syrian government put the death toll at 3,838 - 2,493 civilians and 1,345 security forces personnel.